What is the author's style in Wintergirls by Laurie Halse Anderson?

Wintergirls is told in the first-person and limited omniscience point of view of Lia Overbrook. Although the narration of the novel is completely reliable, it takes the reader through the seemingly endless twists and turns of Lia's fragile emotional state as she comes to grips with Cassie's death and her own eating disorder.